Circuit breaker panel fan runs continuously

robebaba · 07-20-2019, 09:36 AM

My 2014 keystone hideout circuit breaker panel fan runs continuously. I'm plugged into shore power but the fan surges occasionally. Could a bad battery cause that? Could it also be a bad converter? can an amateur with limited electrical knowledge replace the circuit breaker panel or converter? I believe both batteries are not being recharged properly.when the receptacle / converter circuit breaker is switched off, the lights are becoming dimmer. I'm trying to troubleshoot the problem.

UPDATE: Got a second new battery and everything is back to normal. Thanks so much for all your inputs. I'd never have done it without your help.

Lee · 07-20-2019, 09:42 AM

Hi,

The way I understand it the fan is thermally controlled. The harder the converter works the more heat it produces and cycles the fan.

How hot is it inside the RV as this will be a factor?

Have you measured the voltage across the batteries to see how much charge they are getting?

Lee

**JRTJH** · 07-20-2019, 10:44 AM

First, let's properly establish some "item names":

The Power Distribution Center (8900 for 30 amp trailers or 9900 for 50 amp trailers) is the electrical distribution system: both the AC circuit breakers and the DC fuse panel.

The circuit breaker panel distributes the AC side of the power system and does not have a cooling fan.

The fuse panel distributes the DC side of the power system and does not have a cooling fan.

The CONVERTER/CHARGER (changes 120VAC to 12VDC) is mounted behind/within the Power Distribution Center and it has a cooling fan located on it. That fan is thermally controlled and variable speed, depending on the amperage demand from the trailer systems. The larger the DC power demand, the warmer the transformers become and the faster the fan blades turn.

When you dry camp or use your trailer batteries for power, they discharge their stored energy. When you first turn on (plug in) the shore power cord, the converter/charger senses the charge state of the battery and immediately ramps up power conversion to meet the charge requirements (higher amperage output means faster fan speed). As your battery charge status nears completion, the amperage "ramps down" and the fan slows down. If you turn on lights or use other 12VDC components like a fan or furnace or control systems on refrigerator or water heater, slide motors or awning motor or the 12 VDC jacks/landing gear, that demand will cause the converter to increase amperage output and result in the fan speed increasing....

So, with the above being considered, depending on the charge status of your battery bank and/or the amount of 12 volt demand on the converter/charger, as soon as you plug in shore power, as the converter/charger starts converting 120VAC to 12VDC, it will start producing heat (higher amps means more heat) and the fan will begin to turn, speed depending on heat/amperage being produced.

It's normal for the fan to start at about 2 or 3 amps output and begin speeding up as amperage output increases. Many people don't notice the fan until the amperage output of the converter/charger is "up there". Reducing 12 VDC demand will usually result in slower, more quiet fan operation.

The fan can get "off balance" from dust, dirt, pet hair, etc, so cleaning the blades occasionally will often reduce the vibration and stop the distraction.

If your fan is running continuously, then either you have an increased demand from the battery (possibly a bad cell or an internal problem) or you may have 12 volt drains that you aren't considering. Maybe there's a light or a heat strip that's turned on and that has been forgotten? As for lights, usually the fan won't turn on with one or two incandescent bulbs and the third light bulb will "trigger the fan". So, opening the refrigerator door while the outside porch light and the bathroom light are turned on may be just enough amperage draw (along with minimal battery charging) to keep the fan running "24/7".....

If you're concerned with the converter thermal system not operating, disconnect the battery terminals and turn off all the 12 VDC items. If the fan goes off, the thermal controls are functioning. As you turn on 12 volt items, the fan should begin to spin and get faster as you increase the DC load. If the fan continues to run, then you'll need to troubleshoot why it's running with no load and you may have a bad converter. But, if the fan stops when the battery is disconnected, chances are the converter is OK.

Often, the fan in the converter/charger is operating normally and the reason that the owner "notices it" is because the blades are dirty and making more noise than they used to (when they were clean). Usually, just cleaning the fan blades is all that's needed, but it doesn't hurt to check the system by disconnecting the battery, turning on DC loads to make sure the fan starts and increases with increasing DC demand.

**sourdough** · 07-20-2019, 10:50 AM

With what you describe and a 2014 trailer I would ask what is the condition of your batteries, the last time you checked them and if you do regular maintenance on them. If you are just running all kinds of DC powered "stuff" that could account for the continuous fan as well. One thing you can do going forward, if you haven't, is replace all lights with LEDs, but for now I would determine the battery situation.

robebaba · 07-20-2019, 12:32 PM

One battery checked bad. I'm replacing it and will see what happens after reestablishing all connections. Wish me luck.

robebaba · 07-20-2019, 12:33 PM

Inside is about 80 degrees day, 50 degrees at night.

**sourdough** · 07-20-2019, 12:41 PM

If you have 2 batteries and "one" is bad, replace them both. Chances are very high that running with one bad battery has damaged the other and it will start cannibalizing the new battery as soon as you install it. It is always preferable to replace both batteries at the same time if you have 2.

travelin texans · 07-20-2019, 12:58 PM

Quote:

Originally Posted by sourdough

If you have 2 batteries and "one" is bad, replace them both. Chances are very high that running with one bad battery has damaged the other and it will start cannibalizing the new battery as soon as you install it. It is always preferable to replace both batteries at the same time if you have 2.

Ditto! If it has 2 batteries replace both at the same time with true deep cycle batteries. If they list CCA/CA numbers on them they aren't what you want or need, only Ah listed & the more the better.

robebaba · 07-20-2019, 03:09 PM

Many thanks for the electrical lesson. That explains a lot. I replaced one battery, but fan still runs with everything off, frig, lights, etc. I had checked the fan earlier and it had a small amount of dust on blade edges. I cleaned them off fairly well. I'll try disconnecting the batteries and turn on DC lights, tv, etc to see if fan still runs. Fan has been running with everything off. The battery I didn't replace has a fizzing sound and I wonder if it is actually bad too although Riley's machine said it was good. My battery button on the Monitor Panel shows Charged.

**sourdough** · 07-20-2019, 03:45 PM

Quote:

Originally Posted by robebaba

Many thanks for the electrical lesson. That explains a lot. I replaced one battery, but fan still runs with everything off, frig, lights, etc. I had checked the fan earlier and it had a small amount of dust on blade edges. I cleaned them off fairly well. I'll try disconnecting the batteries and turn on DC lights, tv, etc to see if fan still runs. Fan has been running with everything off. The battery I didn't replace has a fizzing sound and I wonder if it is actually bad too although Riley's machine said it was good. My battery button on the Monitor Panel shows Charged.

You need to replace that 2nd battery right away before you damage the new one. You also need to check the output of the converter to make sure it hasn't gone south and is overcharging your batteries.

robebaba · 07-20-2019, 04:05 PM

I just disconnected both batteries and the fan went off. As I turned lights on, the fan started turning and got louder as more lights were turned on. Sounds like the inverter is okay. Fizzing sound from "good" battery may indicate that it's actually bad too?

**sourdough** · 07-20-2019, 04:17 PM

A good battery shouldn't fizz. It needs to be replaced regardless since you replaced the other. When you do I suspect your issues will be resolved. If not, then you need to dig into the converter but as new as it is I would bet on the battery unless something has happened to the converter for some reason.

Edit: What kind of battery(s) are you buying? As Danny mentioned previously a true deep cycle is what you need but may not be available to you. You should have, at least, a "marine/rv" deep cycle battery.

**chuckster57** · 07-21-2019, 07:57 AM

and replace BOTH AT THE SAME TIME.

Jackson62 · 03-16-2022, 06:27 PM

Quote:

Originally Posted by JRTJH

First, let's properly establish some "item names":

The Power Distribution Center (8900 for 30 amp trailers or 9900 for 50 amp trailers) is the electrical distribution system: both the AC circuit breakers and the DC fuse panel.

The circuit breaker panel distributes the AC side of the power system and does not have a cooling fan.

The fuse panel distributes the DC side of the power system and does not have a cooling fan.

The CONVERTER/CHARGER (changes 120VAC to 12VDC) is mounted behind/within the Power Distribution Center and it has a cooling fan located on it. That fan is thermally controlled and variable speed, depending on the amperage demand from the trailer systems. The larger the DC power demand, the warmer the transformers become and the faster the fan blades turn.

When you dry camp or use your trailer batteries for power, they discharge their stored energy. When you first turn on (plug in) the shore power cord, the converter/charger senses the charge state of the battery and immediately ramps up power conversion to meet the charge requirements (higher amperage output means faster fan speed). As your battery charge status nears completion, the amperage "ramps down" and the fan slows down. If you turn on lights or use other 12VDC components like a fan or furnace or control systems on refrigerator or water heater, slide motors or awning motor or the 12 VDC jacks/landing gear, that demand will cause the converter to increase amperage output and result in the fan speed increasing....

So, with the above being considered, depending on the charge status of your battery bank and/or the amount of 12 volt demand on the converter/charger, as soon as you plug in shore power, as the converter/charger starts converting 120VAC to 12VDC, it will start producing heat (higher amps means more heat) and the fan will begin to turn, speed depending on heat/amperage being produced.

It's normal for the fan to start at about 2 or 3 amps output and begin speeding up as amperage output increases. Many people don't notice the fan until the amperage output of the converter/charger is "up there". Reducing 12 VDC demand will usually result in slower, more quiet fan operation.

The fan can get "off balance" from dust, dirt, pet hair, etc, so cleaning the blades occasionally will often reduce the vibration and stop the distraction.

If your fan is running continuously, then either you have an increased demand from the battery (possibly a bad cell or an internal problem) or you may have 12 volt drains that you aren't considering. Maybe there's a light or a heat strip that's turned on and that has been forgotten? As for lights, usually the fan won't turn on with one or two incandescent bulbs and the third light bulb will "trigger the fan". So, opening the refrigerator door while the outside porch light and the bathroom light are turned on may be just enough amperage draw (along with minimal battery charging) to keep the fan running "24/7".....

If you're concerned with the converter thermal system not operating, disconnect the battery terminals and turn off all the 12 VDC items. If the fan goes off, the thermal controls are functioning. As you turn on 12 volt items, the fan should begin to spin and get faster as you increase the DC load. If the fan continues to run, then you'll need to troubleshoot why it's running with no load and you may have a bad converter. But, if the fan stops when the battery is disconnected, chances are the converter is OK.

Often, the fan in the converter/charger is operating normally and the reason that the owner "notices it" is because the blades are dirty and making more noise than they used to (when they were clean). Usually, just cleaning the fan blades is all that's needed, but it doesn't hurt to check the system by disconnecting the battery, turning on DC loads to make sure the fan starts and increases with increasing DC demand.

This has been very helpful. I just bought a 2019 Jayco travel trailer and was assured that I have fresh batteries and that everything has been through the shop and....etc etc.

The fan runs continuously when I connect to shore power. I am going to employ your tutorial tomorrow to see if there is a problem with the inverter or the batteries or???

Thank you!!!

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